Looking at the volume of posts and users to the forum instantly, and the potential for growth. I have to say (sorry) that its a mistake not to be going with a full feature rich piece of forum software.
IPB or vBullitin are the top tier.. But even PHPBB or SMF etc are more feature rich.
The looks and feels like a joomla ?? and thats works fine for small sites but just lacks that polish and scaleability of the big names. Stuff like thread subscriptions, complex boolean searches, etc etc etc (its a long list) are all ready built.
I know that wont be welcome, and suspect it wont be heeded after all the hard work in setting up this site, but having done a few user communities on different platforms, and seeing the size that this one is even at launch, thats my 0.002 Au grammes.